Preliminary synthesis and mechanical property of titanium beryllide pebbles with different chemical compositions

Kim, Jae-Hwan; Nakamichi, Masaru

Journal of Alloys and Compounds, 585, p.63 - 68, 2014/02

https://doi.org/10.1016/j.jallcom.2013.09.103

Evaluation of debris bed self-leveling behavior; A Simple empirical approach and its validations

Cheng, S.; Tagami, Hirotaka; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu; Zhang, B.*; Matsumoto, Tatsuya*; Morita, Koji*

Annals of Nuclear Energy, 63, p.188 - 198, 2014/01

https://doi.org/10.1016/j.anucene.2013.07.050

DFT study on the electronic structure and chemical state of americium in an (Am,U) mixed oxide

Suzuki, Chikashi; Nishi, Tsuyoshi; Nakada, Masami; Tsuru, Tomohito; Akabori, Mitsuo; Hirata, Masaru; Kaji, Yoshiyuki

Journal of Physics and Chemistry of Solids, 74(12), p.1769 - 1774, 2013/12

https://doi.org/10.1016/j.jpcs.2013.07.006

We investigated the electronic state of a CaF-type (Am,U) mixed oxide using the all-electron full potential linear augmented plane wave method and compared it with those of AmO, AmO, UO, and LaUO. The valence of Am in the mixed oxide was close to that of AmO and the valence of U in the mixed oxide was pentavalent. The electronic structure of AmO was different from that of AmO, particularly just above the Fermi level. In addition, the electronic states of Am and U in the mixed oxide were similar to those of trivalent Am and pentavalent U oxides. These electronic states reflected the high oxygen potential of AmO and the heightened oxygen potential resulting from the addition of Am to UO and also suggested the occurrence of charge transfer from Am to U in the solid solution process.

Controllable fabrication of amorphous Si layer by energetic cluster ion bombardment

Lavrentiev, V.*; Vorliek, V.*; Dejneke, A.*; Chvostova, D.*; Jger, A.*; Vacik, J.*; Jastrabik, L.*; Naramoto, Hiroshi*; Narumi, Kazumasa

Vacuum, 98, p.49 - 55, 2013/12

https://doi.org/10.1016/j.vacuum.2013.05.017

Measurement of non-condensable gas in a PWR small-break LOCA simulation test with LSTF for OECD/NEA ROSA project and RELAP5 post-test analysis

Takeda, Takeshi; Owada, Akihiko; Nakamura, Hideo

Experimental Thermal and Fluid Science, 51, p.112 - 121, 2013/11

https://doi.org/10.1016/j.expthermflusci.2013.07.007

Graphene growth and carbon diffusion process during vacuum heating on Cu(111)/AlO substrates

Ogawa, Shuichi*; Yamada, Takatoshi*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Hasegawa, Masataka*; Teraoka, Yuden; Takakuwa, Yuji*

Japanese Journal of Applied Physics, 52(11), p.110122_1 - 110122_8, 2013/11

https://doi.org/10.7567/JJAP.52.110122

Optimization of synthesis conditions for plasma-sintered beryllium-titanium intermetallic compounds

Kim, Jae-Hwan; Nakamichi, Masaru

Journal of Alloys and Compounds, 577, p.90 - 96, 2013/11

https://doi.org/10.1016/j.jallcom.2013.04.185

Preliminary characterization of plasma-sintered beryllides as advanced neutron multipliers

Nakamichi, Masaru; Kim, Jae-Hwan; Munakata, Kenzo*; Shibayama, Tamaki*; Miyamoto, Mitsutaka*

Journal of Nuclear Materials, 442(1-3), p.S465 - S471, 2013/11

https://doi.org/10.1016/j.jnucmat.2012.11.011

Irradiation response in weldment and HIP joint of reduced activation ferritic/martensitic steel, F82H

Hirose, Takanori; Sokolov, M. A.*; Ando, Masami; Tanigawa, Hiroyasu; Shiba, Kiyoyuki; Stoller, R. E.*; Odette, G. R.*

Journal of Nuclear Materials, 442(1-3), p.S557 - S561, 2013/11

https://doi.org/10.1016/j.jnucmat.2013.05.063

Development of high-grade VPS-tungsten coatings on F82H reduced activation steel

Tokunaga, Tomonori*; Watanabe, Hideo*; Yoshida, Naoaki*; Nagasaka, Takuya*; Kasada, Ryuta*; Lee, Y.-J.*; Kimura, Akihiko*; Tokitani, Masayuki*; Mitsuhara, Masatoshi*; Hinoki, Tatsuya*; et al.

Journal of Nuclear Materials, 442(1-3), p.S287 - S291, 2013/11

https://doi.org/10.1016/j.jnucmat.2012.11.004

X-ray diffraction study on microstructures of shot/laser-peened AISI316 stainless steel

Kumagai, Masayoshi*; Akita, Koichi; Itano, Yuta*; Imafuku, Muneyuki*; Oya, Shinichi*

Journal of Nuclear Materials, 443(1-3), p.107 - 111, 2013/11

https://doi.org/10.1016/j.jnucmat.2013.07.010

Microstructural features of AISI316 stainless steels processed by shot peening (SP) and laser peening (LP) were studied using X-ray diffraction line profile analyses. Both specimens exhibited similar compressive residual stress profiles. Although the number of dislocations was increased and the crystallites were refined with both processes, the dislocation density in the SP specimen was significantly greater than that in the LP specimen. The crystallite size in the SP specimen was one-third that in the LP specimen. The SP process induced martensite transformation. The variations in the microstructural features differed between samples subjected to the two processes. The SP process resulted in a greater variation in the microstructural features in a sample in which residual stresses similar to that induced by the LP process were induced. Thus, the variations in the microstructural features differed depending on the deformation process.

Crystal structure of endo-1,4--glucanase from

Arimori, Takao*; Ito, Akihiro*; Nakazawa, Masami*; Ueda, Mitsuhiro*; Tamada, Taro

Journal of Synchrotron Radiation, 20(6), p.884 - 889, 2013/11

https://doi.org/10.1107/S0909049513021110

The saccharification process is essential for bioethanol production from woody biomass including celluloses. Cold-adapted cellulase, which has sufficient activity at low temperature ( 293 K), is capable of reducing heating costs during the saccharification process and is suitable for simultaneous saccharification and fermentation. Endo-1,4--glucanase from the earthworm Eisenia fetida (EF-EG2) belonging to glycoside hydrolase family 9 has been shown to have the highest activity at 313 K, and also retained a comparatively high activity at 283 K. The recombinant EF-EG2 was purified expressed in Pichia pastoris, and then grew needle-shaped crystals with dimensions of 0.02 0.02 1 mm. The crystals belonged to the space group P3221 with unit-cell parameters of = =136 , = 55.0 ,. The final model of EF-EG2, including 435 residues, two ions, seven crystallization reagents and 696 waters, was refined to a crystallographic -factor of 14.7% (free -factor of 16.8%) to 1.5 , resolution. The overall structure of EF-EG2 has an (/) barrel fold which contains a putative active-site cleft and a negatively charged surface. This structural information helps us understand the catalytic and cold adaptation mechanisms of EF-EG2.

Spin state of Co in LaCo RhO investigated by structural phenomena

Asai, Shinichiro*; Okazaki, Ryuji*; Terasaki, Ichiro*; Yasui, Yukio*; Kobayashi, Wataru*; Nakao, Akiko*; Kobayashi, Kensuke*; Kumai, Reiji*; Nakao, Hironori*; Murakami, Yoichi*; et al.

Journal of the Physical Society of Japan, 82(11), p.114606_1 - 114606_6, 2013/11

https://doi.org/10.7566/JPSJ.82.114606

Neutron and synchrotron X-ray diffraction for LaCo RhO have been carried out in order to investigate the structural properties related with the spin state of Co ions. We have found that the values of the Co(Rh)-O bond lengths in the Co(Rh)O octahedron of LaCoRhO are nearly identical at 10 K. The lattice volume for the Rh substituted samples decreases with the thermal expansion coefficient similar to that of LaCoO from room temperature, and ceases to decrease around 70 K. These experimental results favor a mixed state consisting of the high-spin state and low-spin state Co ions, and suggest that the high-spin state Co ions are thermally excited in addition to those pinned by the substituted Rh ions.

Numerical simulation of relocation behavior of molten debris in reactor pressure vessel on severe accident

Yamashita, Susumu; Takase, Kazuyuki; Yoshida, Hiroyuki

Nihon Kikai Gakkai Dai-26-Kai Keisan Rikigaku Koenkai Rombunshu (CD-ROM), p.704_1 - 704_2, 2013/11

In order to understand phenomenologically, we have been developing the numerical simulation method for predicting the melting core behavior including solidification and relocation based on the multi-phase thermal-hydraulic simulation models. In this code, each of gas, liquid and solid phase are treated individually, and interface between two phases are simulated directly. In this paper, the developed code was applied to numerical simulations of the melting behavior of the simulated fuel assemblies and reactor structures. In the simulation, complicated structures in the BWR lower plenum were simply modeled. From the present numerical results, it was confirmed that relocation of molten debris in the RPV can be simulated by the currently developed code including effects of melting and solidification of debris in two components flow simulation. And it was also confirmed that relocation of molten debris with decay heat could be simulated in three components flow simulation.

Numerical evaluation of influence of coolant flow direction upon thermal hydraulics in SCWR rod bundle

Misawa, Takeharu; Yoshida, Hiroyuki; Takase, Kazuyuki

Nihon Kikai Gakkai Dai-26-Kai Keisan Rikigaku Koenkai Rombunshu (CD-ROM), p.702_1 - 702_2, 2013/11

no abstracts in English

Study on ion irradiation response of Gafchromic films for the intensity distribution measurement of a large-area beam

Yuri, Yosuke; Ishizaka, Tomohisa; Yuyama, Takahiro; Ishibori, Ikuo; Okumura, Susumu

Nuclear Instruments and Methods in Physics Research A, 727, p.40 - 45, 2013/11

https://doi.org/10.1016/j.nima.2013.05.160

Modification of teflon surface by proton microbeam and nitrogen ion beam

Kitamura, Akane; Sato, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Kobayashi, Tomohiro*

Nuclear Instruments and Methods in Physics Research B, 314, p.82 - 85, 2013/11

https://doi.org/10.1016/j.nimb.2013.05.040

Preparation of tungsten carbide nanoparticles by ion implantation and electrochemical etching

Kato, Sho; Yamaki, Tetsuya; Yamamoto, Shunya; Hakoda, Teruyuki; Kawaguchi, Kazuhiro; Kobayashi, Tomohiro*; Suzuki, Akihiro*; Terai, Takayuki*

Nuclear Instruments and Methods in Physics Research B, 314, p.149 - 152, 2013/11

https://doi.org/10.1016/j.nimb.2013.05.052

We implanted 100 keV W in unpolished GC substrates at nominal fluences up to ions/cm. The implanted samples were electrochemically anodized in a NaOH aqueous solution to etch the surface layer. The analyses were performed by X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectrometry (RBS), and transmission electron microscopy (TEM). XPS W 4f spectra indicated the formation of carbides as reported previously. The electrochemical etching clearly increased the W concentration on the surface. According to the RBS results, half of the implanted W atoms were retained in the substrate, while the rest should escape to the etching solution. The cross-sectional TEM image revealed a uniform distribution of WC particles with a diameter of less than 10 nm just near the surface region.

Applied-voltage dependence on conductometric track etching of poly(vinylidene fluoride) films

Nuryanthi, N.*; Yamaki, Tetsuya; Koshikawa, Hiroshi; Asano, Masaharu; Sawada, Shinichi; Hasegawa, Shin; Maekawa, Yasunari; Katsumura, Yosuke*

Nuclear Instruments and Methods in Physics Research B, 314, p.95 - 98, 2013/11

https://doi.org/10.1016/j.nimb.2013.05.035

Our efforts have been focused on ion-track etched membranes of poly(vinylidene fluoride) (PVDF). This study deals with the effect of the transmembrane potential applied during the conductometry in order to offer a higher degree of freedom to control the pore size. We can say that higher voltage application during the conductometry would accelerate the etching in the tracks. The electrophoretic migration of dissolved products occurring out of each pore might be one of the reasons for this enhanced pore evolution and growth.

Effects of van der Waals interaction for first-principles calculations on iron-based superconductors

Nakamura, Hiroki; Machida, Masahiko

Physica C, 494, p.9 - 12, 2013/11

https://doi.org/10.1016/j.physc.2013.04.040

We investigate the effect of the van der Waals interaction on various iron-based superconductors by using first-principles density functional theory with van der Waals density functional (vdW-DF), which implements non-local and long-ranged interactions. vdW-DF reproduces well the lattice constants of FeSe, while the crystal structures of other compounds are not sensitive to the van der Waals interaction. Clear influence on the electronic structure is not found, and then the van der Waals interaction hardly affects superconductivity in iron-based superconductors.

Magnetic properties of RFeO (R=Yb and Lu)

Yoshii, Kenji; Ikeda, Naoshi*; Fukuyama, Ryota*; Nagata, Tomoko*; Kambe, Takashi*; Yoneda, Yasuhiro; Fukuda, Tatsuo; Mori, Shigeo*

Solid State Communications, 173, p.34 - 37, 2013/11

https://doi.org/10.1016/j.ssc.2013.08.030

We have investigated the magnetic properties of RFeO (R=Yb and Lu), which belongs to the homologous family of electronic ferroelectric RFeO. Magnetization measurements show ferrimagnetic ordering at the Neel temperature (T) of about 270 K, which is slightly higher than that of RFeO (T about 230-250 K). Observation of spin glass and exchange bias shows a coexistence of ferromagnetic and antiferromagneticinteractions, similarly to RFeO. This situation gives rise to a complex magnetic change and a broad peak of magnetic entropy change. Some characteristics, such as refrigeration temperatures higher than in RFeO, seem to offer a possibility of this system to applications.

Protein and water confined in nanometer-scale reverse micelles studied by near infrared, terahertz, and ultrafast visible spectroscopies

Murakami, Hiroshi

Advances in Protein Chemistry and Structural Biology, 93, p.183 - 211, 2013/10

https://doi.org/10.1016/B978-0-12-416596-0.00006-3

no abstracts in English

Release of mantle and crustal helium from a fault following an inland earthquake

Umeda, Koji; Asamori, Koichi; Kusano, Tomohiro

Applied Geochemistry, 37, p.134 - 141, 2013/10

https://doi.org/10.1016/j.apgeochem.2013.07.018

This study was undertaken to elucidate spatial and temporal changes of He/He ratios around a source region before and after an inland earthquake using both new and existing helium isotope data from hot spring and drinking water wells. Most gas samples near the seismic source region are characterized by increase in postseismic He/He ratios. In contrast, the postseismic ratios decrease by up to about 30% away from the seismic source region. Episodic faulting could release accumulated radiogenic helium from host rocks, or enhance the transfer of mantle volatiles through permeable fault zones, such that subsequent fluid flow proximal to the source region could then explain the spatio-temporal variations in He/He ratios.

Mechanical properties of full austenitic welding joint at cryogenic temperature for the ITER toroidal field coil structure

Iguchi, Masahide; Saito, Toru; Kawano, Katsumi; Chida, Yutaka; Nakajima, Hideo; Ogawa, Tsuyoshi*; Katayama, Yoshinori*; Ogata, Hiroshige*; Minemura, Toshiyuki*; Tokai, Daisuke*; et al.

Fusion Engineering and Design, 88(9-10), p.2520 - 2524, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.02.165

ITER TFC structures are large welding structures made of heavy thick stainless steels. JAEA plans to apply narrow gap TIG welding with FMYJJ1 which is full austenitic stainless filler material to manufacture TFC structure. FMYJJ1 is specified in "Codes for Fusion Facilities -Rules on Superconducting Magnet Structure (2008)". In order to evaluate effect of base material combinations and thickness of welded joint on tensile properties at 4 K, tensile tests were conducted at 4 K by using tensile specimens taken from 40 mm thickness weld joints of four combinations and 200 mm thickness ones of two combinations of base materials. These weld joints were manufactured by one side narrow gap TIG welding with FMYJJ1. As the results, it was confirmed that yield and tensile strengths of welded joint at 4K were decreased with decreasing of nitrogen of base material, and there were no large distribution of strengths at 4 K along the thickness of welded joints of 200 mm thickness.

Demonstration on endurance of ion exchange membrane immersed in high-concentration tritiated water under the Broader Approach activities

Iwai, Yasunori; Sato, Katsumi; Kawamura, Yoshinori; Yamanishi, Toshihiko

Fusion Engineering and Design, 88(9-10), p.2319 - 2322, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.05.051

The Nafion ion exchange membrane is a key material for electrolysis cells of the water detritiation system. Endurance of ion exchange membrane immersed into high-concentration tritiated water has been demonstrated under the Broader Approach activities, as a R&D on endurance of fuel cycle components at high tritium exposure. Long-term exposure of Nafion ion exchange membrane into 1.38 TBq/kg of tritiated water was conducted at room temperature for up to 2 years. The curves of percent elongation at break vs. dose and tensile strength vs. dose for the Nafion membranes immersed into tritiated water were well consistent with those for Nafion membranes irradiated to an equivalent dose with rays and electron beams. The results of ferric Fenton test indicated that the degradation directly by radiation was dominant at room temperature compared with that by reactions with radicals produced from water radiolysis. The curve of ion exchange capacity vs. dose for the Nafion membranes immersed into tritiated water was also well consistent with that for Nafion membranes irradiated to an equivalent dose with rays and electron beams. These results showed that the irradiation tests with rays and electron beams were effective to predict a degradation behavior of ion exchange membrane immersed into high-concentration tritiated water.

Fabrication and installation of equilibrium field coils for the JT-60SA

Tsuchiya, Katsuhiko; Kizu, Kaname; Murakami, Haruyuki; Kashiwa, Yoshitoshi; Yoshizawa, Norio; Yoshida, Kiyoshi; Hasegawa, Mitsuru*; Kuno, Kazuo*; Nomoto, Kazuhiro*; Horii, Hiroyuki*

Fusion Engineering and Design, 88(6-8), p.551 - 554, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.02.096

The programme of constructing JT-60SA device is progressing under the framework of the Broader Approach project. Superconducting poloidal field (PF) coil system, which was decided to be procured by Japan, consists of a central solenoid (CS) with four solenoid modules and six equilibrium field (EF) coils. Each of EF coil has individual diameters, 4.5 to 12 m. Fabrication of EF4 coil, which is set at the lowermost of torus, was started from the beginning of 2009 as a first EF coil. EF4 coil has ten double pancake (DP) coils, and sizes of circularity were measured for all DP coil after curing process. Maximum error of circularity was 3.1 mm, which was nearly a half of the design tolerance, 6 mm. After stacking these DP coils, winding pack of EF4 was completed in the spring of 2012. After optimizing the positions of DP coils to cancel the error of circulation which each DP coil has, error of radial current centre of DP coils will be achieved in the range between + 0.2 to - 0.4 mm. Structural analysis of terminal structure was also performed. Terminal part has a pair of conductors bended toward the lower side of winding pack. A side of them (positive terminal) was covered by stainless steel armor to prevent the movement by electromagnetic force because a length of conductor was longer due to starting from the top of winding pack. Another side (negative terminal) was not covered by armor in the first design because this length was relatively short. However, it was clear on the structural analysis that mechanical strength of insulation around this terminal was not sufficient. Therefore, we also reinforced this side with stainless steel. From this April, fabrication of EF coils with large bore (larger than 8 m of diameter) will be started at the facility built in JAEA Naka site. In this paper, we will discuss about technological problem during the fabrication of large bore EF coils, such as temperature control at the winding process.

Development of a linear motion antenna for the JT-60SA ECRF system

Moriyama, Shinichi; Kobayashi, Takayuki; Isayama, Akihiko; Hoshino, Katsumichi; Suzuki, Sadaaki; Hiranai, Shinichi; Yokokura, Kenji; Sawahata, Masayuki; Terakado, Masayuki; Hinata, Jun; et al.

Fusion Engineering and Design, 88(6-8), p.935 - 939, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.02.019

An antenna having a first mirror driven in the linear motion (LM) and a fixed second mirror was proposed for electron cyclotron range of frequency (ECRF) heating and current drive system, to minimize the risk of cooling-water-leakage. Basic mechanical feasibilities of the bellows covering the movable structures of the antenna were previously investigated using a mock-up. This time, a support structure of the shaft has been designed using a metallic sliding bearing with solid lubricant. The sliding bearing can support combination of linear and rotational motions while a ball bearing supports either linear or rotational motion. We have newly installed the sliding bearing into the mock-up. A vacuum pumping test has been carried out paying attention to the influence of the solid lubricant by mass analysis. To design the LM antenna for JT-60SA in detail, heating and current drive characteristics for typical experimental scenarios of JT-60SA has been investigated by calculation.

Structural analyses of HV bushing for ITER heating NB system

Tobari, Hiroyuki; Inoue, Takashi; Taniguchi, Masaki; Kashiwagi, Mieko; Umeda, Naotaka; Dairaku, Masayuki; Yamanaka, Haruhiko; Watanabe, Kazuhiro; Sakamoto, Keishi; Kuriyama, Masaaki*; et al.

Fusion Engineering and Design, 88(6-8), p.975 - 979, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.02.020

The HV bushing, one of the ITER NB components, which is to be procured by JADA, is a multi-conductor feed through composed of five-stage double-layered insulator columns with large brazed ceramic ring and fiber reinforced plastic (FRP) ring. The HV bushing is a bulk head between insulation gas at 0.6 MPa and vacuum. The FRP ring is required to sustain the pressure load, seismic load and dead weight. Brazing area of the ceramic ring with Kovar is required to maintain vacuum leak tightness and pressure tightness against the air filled at 0.6 MPa. To design the HV bushing satisfying the safety factor of 3.5, mechanical analyses were carried out. As for the FRP ring, it was confirmed that isotropic fiber cloth FRP rings should be used for sufficient strength against shear stress. Also, shape and fixation area of the Kovar sleeve were modified to lower the stress at the joint area. As a result, a design of the insulator for the HV bushing was established satisfying the requirement.

Trial synthesis of LiBeO for high-functional tritium breeders

Hoshino, Tsuyoshi; Oikawa, Fumiaki; Natori, Yuri*; Kato, Kenichi*; Sakka, Tomoko*; Nakamura, Mutsumi*; Tatenuma, Katsuyoshi*

Fusion Engineering and Design, 88(9-10), p.2268 - 2271, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.05.013

Lithium titanate with additional Li (LiTiO) and lithium orthosilicate (LiSiO) is one of the most promising candidates for use in a tritium breeder because of its good chemical and mechanical stabilities. Currently, mixtures of tritium breeder pebble and neutron multiplier (Be or BeTi) pebble are being considered for use in increasing the tritium breeding ratio in a breeding blanket. However, lithium and beryllium are gradually reacted under practical operating conditions, and therefore a high-functional tritium breeder such as lithium beryllium oxide (LiBeO) needs to be developed to compensate for this reactive characteristic under high temperature use. In this study, methods of synthesizing LiBeO have been extensively investigated by means of solid-phase reaction. The solid-phase reaction of LiOH(HO) and BeO is a suitable synthesis method for lithium beryllium oxide (LiBeO). It is expected that single-phase LiBeO will be stable under the mixture conditions of a tritium breeder and neutron multiplier in the blanket region at high temperatures.

Re-defining failure envelopes for silicon carbide composites based on damage process analysis by acoustic emission

Nozawa, Takashi; Ozawa, Kazumi; Tanigawa, Hiroyasu

Fusion Engineering and Design, 88(9-10), p.2543 - 2546, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.05.054

A SiC/SiC composite is a promising candidate for a fusion DEMO blanket. Due to the inherent quasi-ductile failure of composites, determining failure scenario for this class of composites is undoubtedly important to develop design codes in practical use of them. This study aims to evaluate the failure behavior of the quasi-ductile SiC/SiC composites to provide a strength map. For this purpose, detailed tensile, compressive and in-plane shear failure behaviors were evaluated by the acoustic emission (AE) technique. The AE results distinguished damage accumulation processes by wavelet analysis. Of particular emphasis is that matrix cracking occurred prior to the PLS by both tensile and compressive loadings because the rough-surface of SiC fibers resulted in the strong frictional stress at the fiber/matrix (F/M) interface. In this paper, an updated failure envelope will be provided by referring the actual matrix cracking stresses as more realistic and reasonable failure criteria.

Adsorption rate of hydrogen isotopes on Ca-mordenite

Kawamura, Yoshinori; Edao, Yuki; Yamanishi, Toshihiko

Fusion Engineering and Design, 88(9-10), p.2255 - 2258, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.05.021

To develop an adsorbent that is suitable for a separation column of gas chromatograph for hydrogen isotope analysis, the mordenite-type zeolite of which cations (Na) were exchanged with other cations have been prepared and their hydrogen isotope adsorption behavior is being investigated. Then, it has been shown experimentally that mordenite-type zeolite of which cation has been exchanged with Ca (Ca-MOR) has fairly large adsorption capacity. So, breakthrough curves of H (or D) adsorption on Ca-MOR at 194 K and 175 K have been observed and mass transfer coefficients have been estimated from them. The rate-controlling step of hydrogen adsorption is hydrogen diffusion in porous adsorbent. And, isotopic difference of effective diffusivity in Ca-MOR is larger than that in Na-MOR. Therefore, in comparison with Na-MOR, use of Ca-MOR is expected to enhance the hydrogen isotope separation capability.

Benchmark test of TRIPOLI-4 code through simple model calculation and analysis of fusion neutronics experiments at JAEA/FNS

Ota, Masayuki; Takakura, Kosuke; Ochiai, Kentaro; Sato, Satoshi; Konno, Chikara

Fusion Engineering and Design, 88(9-10), p.2160 - 2163, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.02.090

Three-dimensional Monte Carlo transport code is widely used in analyses of radiation protection and shielding, nuclear criticality safety, fission and fusion reactor design and nuclear instrumentation. The MCNP code is worldwide used as the standard code. The TRIPOLI code is adopted as one of ITER neutronics codes, but it is not always used worldwide, particularly in Japan. In this study we examined the basic performance of TRIPOLI through simple model calculations and analysis of iron neutronics experiments with DT neutrons at the Fusion Neutronics Source facility in Japan Atomic Energy Agency. Almost results by TRIPOLI are consistent with ones by MCNP. However, there is a difference between TRIPOLI and MCNP results in some calculations caused mainly by treatment with inelastic scattering data.

Progress of the ITER NBI acceleration grid power supply reference design

Toigo, V.*; Zanotto, L.*; Bigi, M.*; Decamps, H.*; Ferro, A.*; Gaio, E.*; Gutirrez, D.*; Tsuchida, Kazuki; Watanabe, Kazuhiro

Fusion Engineering and Design, 88(6-8), p.956 - 959, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.01.013

This paper reports the progress in the reference design of the Acceleration Grid Power Supply (AGPS) of the ITER Neutral Beam Injector (NBI). The design of the AGPS is very challenging, as it shall be rated to provide about 55 MW at 1 MV dc in quasi steady-state conditions; moreover, the procurement of the system is shared between the European Domestic Agency (F4E) and the Japanese Domestic Agency (JADA), resulting in additional design complication due to the need of a common definition of the interface parameters. A critical revision of the main design choices is presented also in light of the definition of some key interface parameters between the two AGPS subsystems. Moreover, the verification of the fulfillment of the requirements in any operational conditions taking into account the tolerance of the different parameters is also reported and discussed.

Engineering design of the RF input coupler for the IFMIF prototype RFQ linac

Maebara, Sunao; Palmieri, A.*; Mereu, P.*; Ichikawa, Masahiro; Takahashi, Hiroki; Comunian, M.*; Suzuki, Hiromitsu; Pisent, A.*; Sugimoto, Masayoshi

Fusion Engineering and Design, 88(9-10), p.2740 - 2743, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.02.135

Performance evaluation on force control for ITER blanket installation

Aburadani, Atsushi; Takeda, Nobukazu; Shigematsu, Soichiro; Murakami, Shin; Tanigawa, Hisashi; Kakudate, Satoshi; Nakahira, Masataka*; Hamilton, D.*; Tesini, A.*

Fusion Engineering and Design, 88(9-10), p.1978 - 1981, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.02.093

no abstracts in English

Disposal of low-level radioactive waste generated from research, industrial, and medical facilities in Japan

Dohi, Terumi

Genshiryoku Nenkan 2014, p.138 - 139, 2013/10

no abstracts in English

Chapter 2 "Radiation measurement" and Chapter 3 "Measurement and estimation of exposed dose"

Yoshizawa, Michio; Suzuki, Takashi; Noguchi, Masayasu*

Hoshasen Anzen Kanri No Jissai 3-Han, p.39_90 - 91_120, 2013/10

It was decided to revise the book of "Actual Radiation Safety Management", which has been used as a main text for the radiation protection supervisors, in order to reflect the latest amendment of the Radiation Hazards Prevention Act. Then, we revised Chapter 2 "Radiation measurement" and Chapter 3 "Measurement and estimation of exposed dose" of the book, which were the writing parts of the current version, so as to incorporate the most up-to-date information. Main subjects of these revises were the change of radiation and tissue weighting factors in the 2007 recommendations of the International Commission on Radiological Protection (ICRP), update of the information about survey meters and personal dosimeters, clarification of sentences and so on.

Measurement technology for the radiocesium distribution of wide area; Measurement of radiocesium using the fiber detector

Torii, Tatsuo; Sanada, Yukihisa

Isotope News, (714), p.25 - 29, 2013/10

http://www.jrias.or.jp/books/201310_TRACER_TORII_SANADA.pdf

http://www.jrias.or.jp/books/cat3/2013/714.html

no abstracts in English

High temperature reaction tests between high-Cr ODS ferritic steels and U-Zr metallic fuel

Otsuka, Satoshi; Kaito, Takeji; Ukai, Shigeharu*; Inoue, Masaki; Okuda, Takanari*; Kimura, Akihiko*

Journal of Nuclear Materials, 441(1-3), p.286 - 292, 2013/10

https://doi.org/10.1016/j.jnucmat.2013.06.002

The Al addition to ODS ferritic steels considerably improves the compatibility between U-Zr fuel and the ODS steels. The threshold temperature for reaction layer formation is roughly 50K higher in the Al-containing ODS ferritic steels than in those same steels without Al addition. The activity calculation results obtained using general thermodynamic data indicate the possibility that stabilization of the intact alpha-Zr layer by Al addition is the main mechanism for the compatibility improvement by Al addition.

Investigation of a LiCl-KCl-UCl system using a combination of X-ray diffraction and differential thermal analyses

Nakayoshi, Akira; Kitawaki, Shinichi; Fukushima, Mineo; Murakami, Tsuyoshi*; Kurata, Masaki

Journal of Nuclear Materials, 441(1-3), p.468 - 472, 2013/10

https://doi.org/10.1016/j.jnucmat.2013.06.019

Electrorefining is one of the main steps of pyroreprocessing where spent nuclear fuels are recycled. Electrorefining is conducted in a molten salt of LiCl-KCl eutectic (59:41 mol%) containing actinide chlorides (AnCl) at 773 K. In order to operate and maintain the electrorefiner, it is necessary to accumulate fundamental data on LiCl-KCl-AnCl salt such as the melting point. In this study, based on X-ray diffraction and differential thermal analysis, a partial phase diagram of (LiCl-KCl)eut.-UCl pseudo-binary system and partial phase diagram of LiCl-KCl-UCl system were developed, which UCl concentration was up to 20 mol%.

Assessment of residual stress due to overlay-welded cladding and structural integrity of a reactor pressure vessel

Katsuyama, Jinya; Nishikawa, Hiroyuki*; Udagawa, Makoto; Nakamura, Mitsuyuki*; Onizawa, Kunio

Journal of Pressure Vessel Technology, 135(5), p.051402_1 - 051402_9, 2013/10

https://doi.org/10.1115/1.4024617

The residual stresses generated within the weld-overlay cladding and base material of reactor pressure vessel (RPV) steel was evaluated for as-welded and post-welded heat-treated conditions using thermo-elastic plastic creep analyses considering phase transformation. By comparing the analytical results with the experimentally determined values, we found a good agreement for the residual stress distribution within the cladding and the base material. It was shown that considering phase transformation during welding was important for improving the accuracy of residual stress analysis. Using the calculated residual stress distribution, we performed fracture mechanics analyses for an RPV during pressurized thermal shock events. We evaluated the effect of the weld residual stress on the structural integrity of an RPV. The results indicated that consideration of residual stress produced by weld-overlay cladding and PWHT is important for assessing the structural integrity of RPV.

Spin current; Experimental and theoretical aspects

Maekawa, Sadamichi; Adachi, Hiroto; Uchida, Kenichi*; Ieda, Junichi; Saito, Eiji

Journal of the Physical Society of Japan, 82(10), p.102002_1 - 102002_23, 2013/10

https://doi.org/10.7566/JPSJ.82.102002

NWAS: Developments for passive uranium assay system, 2

Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Kado, Kazumi

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 10 Pages, 2013/10

A uranium mass assay system for 200-litter wastes drums applied by NDA method was developed and accumulated the data of the actual uranium bearing wastes drums. The system consists of the 16 pieces of Helium-3 proportional counters for neutron detection generated from U(,n) reaction or U spontaneous fissions with polyethylene moderation and a Germanium solid state detector for ray detection as to determine uranium enrichment. In previous report, some measurement experiences had been introduced briefly. After that satisfactory works had been continued and the uranium determination data of 850 drums had been accumulated approximately. On the other hand considerable problems on the system had been revealed technically or analytically. Such experiences are to be described precisely, in addition newly gained knowledge will be marshaled. Furthermore the next improvement plans are now prepared that will be capable of active neutrons assay for uranium bearing wastes drums.

BRIKEN: Beta delayed neutron emission measurement at RIKEN

Koura, Hiroyuki

Kaku Deta Nyusu (Internet), (106), p.26 - 33, 2013/10

http://www.aesj.or.jp/~ndd/ndnews/pdf106/No106-04.pdf

no abstracts in English

Microstructure characterization of oxide dispersion strengthened steels containing metallic chromium inclusions after high-temperature thermal aging

Otsuka, Satoshi; Yano, Yasuhide; Tanno, Takashi; Kaito, Takeji; Tanaka, Kenya

Materials Transactions, 54(10), p.2018 - 2026, 2013/10

https://doi.org/10.2320/matertrans.M2013217

Microstructure characterizations of 9Cr-oxide dispersion strengthened (ODS) steels were carried out after high-temperature thermal aging to reproduce the anomalous microstructure change that occurred in the BOR-60 irradiation test-formation of abnormally coarse and irregular precipitates a few tens of micrometers in size. In the 9Cr-ODS steel containing metallic Cr inclusions, coarse and irregular precipitates were formed nearby metallic Cr inclusions after the 750C thermal aging for 8,000h. Based on the analyses using energy dispersive X-ray spectrometry (EDX) and electron backscattered pattern (EBSP), coarse and irregular precipitates were identified as M23C6.

Water penetration test using mock protection layer system for multi-layered capping planned in Ningyo-toge Environmental Engnieering Center

Fukushima, Shigeru; Taki, Tomihiro; Saito, Hiroshi; Torikai, Kazuyoshi; Sato, Yasushi*

Nihon Chikasui Gakkai 2013-Nen Shuki Koenkai Koen Yoshi, p.258 - 263, 2013/10

no abstracts in English

Creep-fatigue evaluation of a structural model made of Mod.9Cr-1Mo steel subjected to the cyclic thermal loading

Ando, Masanori; Hasebe, Shinichi; Kobayashi, Sumio; Kasahara, Naoto*; Toyoshi, Akira*; Omae, Takahiro*; Enuma, Yasuhiro*

Nihon Kikai Gakkai M&M 2013 Zairyo Rikigaku Kanfarensu Koen Rombunshu (CD-ROM), p.OS1510_1 - OS1510_3, 2013/10

To validate the failure mode and assess creep-fatigue damage evaluation, a thick cylinder test model made of Mod.9Cr-1Mo steel was subjected to 1,873 cycles of accelerated thermal transient loading using a large-scale sodium loop through which liquid sodium at 600C and 250C flowed repeatedly, with the period of each transient being 2 h and 1 h, respectively. After completion of the test, liquid penetrant testing, a surface observation and hardness testing were performed to characterize failure mode. Based on the finite element analysis, creep-fatigue life was evaluated by applying the JSME FRs code. The failure cycles evaluated by rules described in the JSME FRs code was shown to have a safety margin of greater than 300 times for this system.

Progress of the JT-60SA project

Kamada, Yutaka; Barabaschi, P.*; Ishida, Shinichi; JT-60SA Team; JT-60SA Research Plan Contributors

Nuclear Fusion, 53(10), p.104010_1 - 104010_17, 2013/10

https://doi.org/10.1088/0029-5515/53/10/104010

Preparation of polymer gel dosimeters based on less toxic monomers and gellan gum

Hiroki, Akihiro; Sato, Yuichi*; Nagasawa, Naotsugu; Ota, Akio*; Seito, Hajime; Yamabayashi, Hisamichi*; Yamamoto, Takayoshi*; Taguchi, Mitsumasa; Tamada, Masao; Kojima, Takuji

Physics in Medicine & Biology, 58(20), p.7131 - 7141, 2013/10

https://doi.org/10.1088/0031-9155/58/20/7131

Development of displacement damage model in PHITS and comparison with other codes in a high-energy region

Iwamoto, Yosuke; Niita, Koji*; Sawai, Tomotsugu; Ronningen, R. M.*; Baumann, T.*

Proceedings of 11th Meeting of the Task Force on Shielding Aspects of Accelerators, Targets and Irradiation Facilities (SATIF-11), p.91 - 98, 2013/10

http://www.oecd-nea.org/science/pubs/2013/7157-satif-11.pdf

We have developed the displacement damage model in PHITS using the screened Coulomb scattering and the nuclear reaction model to evaluate the energy of the target PKA created by the projectile and the "secondary particles" which include all particles created from the sequential nuclear reactions. For the high-energy proton and neutron incident reactions, it was found that a target PKA created by the "secondary particles" is more dominant than a target PKA created by the projectile in DPA calculations. Recently, radiation damage models in other codes such as FLUKA, MARS, MCNP have also been developed. As there is few experimental data in a high energy region, an intercomparison of Monte Carlo codes used in the radiation damage calculation is very important for the improvement of models. In the meeting, we will also discuss the comparison between PHITS and FLUKA for the high-energy proton and neutron irradiation.

Materials related to the Ministry of Education, Culture, Sports, Science and Technology's project to measure large-scale radioactive soil contamination due to the Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Plant accident; The Launch of the project

Sakaba, Nariaki

Radioisotopes, 62(10), p.774 - 780, 2013/10

https://doi.org/10.3769/radioisotopes.62.774

Since the various FPs were emitted to the wide range of east Japan from the Tokyo Electric Power Company's Fukushima Daiichi NPP and the half-life of I is eight days short, it is recognized early after the accident that the investigation and measurement of radioactivities should be done as early as possible. The government nuclear hazard task force opted for the "environmental monitoring enhancement project", and specified the MEXT as an organization which carries out the environmental monitoring and the official announcement of the distribution map of with describing radiation dose rate data. In response, MEXT defined the strengthening measure of monitoring, and decided to create a map measuring a large-scale radioactive soil contamination cooperating with the MAFF, Fukushima Prefecture, JAEA, Universities, other research institutes, etc. JAEA was specified as an adjustment organization by MEXT. This paper describes the launch of the project.

Calcium and magnesium-bearing sabugalite from the Tono uranium deposit, central Japan

Nakata, Masataka*; Sasao, Eiji; Komuro, Kosei*

Resource Geology, 63(4), p.404 - 411, 2013/10

https://doi.org/10.1111/rge.12019

Various secondary uranium minerals yield in oxidized zone near surface. These minerals indicate retardation of uranium in oxidized zone. Calcium and magnesium-bearing sabugalite occurs as aggregations of yellowish platy crystals in veinlets or druses in conglomerate from the oxidized parts of the Tono uranium deposit, Central Japan. X-ray powder diffractometry of this mineral has reflections consistent with previous powder diffraction data of sabugalite. Chemical analysis reveals the chemical composition of the minerals. SEM-EDS mapping shows that the mineral is compositionally uniform with no micron-scale layering. Charge of cations including Ca and Mg in the cation-HO layer is 1.98 being identical to that of autunite group minerals. This suggests that the charge balance in the cation-HO layer of the mineral could be made by the alkaline earth or alkaline elements rather than by hydrogen ions.

Research and development of radiation measuring instruments for lake,pond and river sediments, 1

Yanagizawa, Koichi; Hayashi, Toshio*; Oinuma, Masaru*; Takemori, Makoto*; Ishikawa, Takanori*; Okaya, Tomoichi*; Nishigaki, Makoto*

Shadan Hojin Butsuri Tansa Gakkai Dai-129-Kai (Heisei-25-Nendo Shuki) Gakujutsu Koenkai Koen Rombunshu, p.287 - 288, 2013/10

The development of instrument aimed at the measurement of radiation dose in the sediment of lakes, rivers and sea bed been carried out. The radiation level contained in the sediment at the bottom of lake and so on is anticipated to indicate the existence of locally high radiation spots where the diffused radioactive substance is accumulated in ponds, rivers and lakes by rainwater. The radiation dose measurement system this time is to measure -ray by dragging the detector, which is called probe, at the bottom of lakes to understand the radiation dose over wide areas. Furthermore, the measurement of resistivity value at the bottom of lakes is simultaneously dose to presume the condition of sediment.

Unusual sevenfold coordination of Ru in complex hydride NaRuH; Prospect for formation of [FeH] anion

Takagi, Shigeyuki*; Ikeshoji, Tamio*; Matsuo, Motoaki*; Sato, Toyoto*; Saito, Hiroyuki; Aoki, Katsutoshi; Orimo, Shinichi*

Applied Physics Letters, 103(11), p.113903_1 - 113903_4, 2013/09

https://doi.org/10.1063/1.4821260

K-Ar geochronology of fault

Tamura, Hajimu; Sato, Keiko*

Chishitsu Gijutsu, (3), p.21 - 25, 2013/09

K-Ar age of fault is sometimes exclusive fact age of fault activity though the age of fault activity is determined on stratigraphy and ages by different dating methods. This note describes application of K-Ar dating to fault sample. Pseudotachylyte and Authigenic illite in fault gauge are major target material of dating. Sample preparation and determination of age are difficult for both of them and the geochronology is still in development stage. Dating examples of Pseudotachylyte says that sample separation is important to select part which was equilibrate to atomosphere in generation by spot analysis like laser fusion Ar-Ar dating, as illite examples that sample preparation to obtain fine - about 1 micrometer or less - grain and sample determination by inspection with electron microscope or XRD analysis are important.

Investigation methodology for influence of cement material from grouting origin to granite

Uyama, Masao*; Hitomi, Takashi*; Sato, Toshinori

Doboku Gakkai Heisei-25-Nendo Zenkoku Taikai Dai-68-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), 2 Pages, 2013/09

no abstracts in English

The Effect assessment for fast reactor fuel cycle deployment; Improvement of the assessment method

Mukaida, Kyoko; Shiotani, Hiroki; Ono, Kiyoshi; Namba, Takashi

Energy Procedia, 39, p.43 - 51, 2013/09

https://doi.org/10.1016/j.egypro.2013.07.190

In this study, the energy economic model was upgraded to improve the assessment method of the effect assessment for FR cycle deployment. Moreover, based on the assessment results for FR deployment in the world by the energy economic model, the effects of FR exports were assessed. This results show the FR exports have certain impact to domestic economy.

Three-dimensional magnetotelluric inversion using a heterogeneous smoothness-constrained least-squares method

Negi, Tateyuki*; Mizunaga, Hideki*; Asamori, Koichi; Umeda, Koji

Exploration Geophysics, 44(3), p.145 - 155, 2013/09

https://doi.org/10.1071/EG13026

This paper presents a fast algorithm for electromagnetic inversion. The algorithm is distinct for the level of accuracy it attains when bypassing the sensitivity matrix update. A common sensitivity matrix for homogeneous half-space is used in all of the iterations. Instead of a fixed sensitivity matrix, the Laplace filter coefficients at each element are updated based on the spatial differences of resistivity calculated by a reconstructed structure derived from the former iteration. This substitution is expected not only to reduce the computation time required for large-scale inversions, such as those for three-dimensional surveys, but also to allow reconstruction for sharp boundaries in resistivity structures. This algorithm was applied to three-dimensional magnetotelluric inversion in order to confirm the effectiveness. This paper reports the results of several synthetic examples using different resistivity models and conditions.

In situ stress measurement by CCBO in Mizunami Underground Researh Laboratory

Sato, Toshinori; Tanno, Takeo; Sanada, Hiroyuki; Yokoyama, Tatsuya*; Shimoyama, Masahiro*

Heisei-25 Nendo (2013 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.257 - 258, 2013/09

Japan Atomic Energy Agency is operating underground research laboratory projects in order to establish a firm scientific basis for safe geological disposal of HLW. One of these is the Mizunami Underground Research Laboratory (MIU) project focused on crystalline rock. In situ stress measurement by Compact Conical-ended Borehole Overcoring (CCBO) are conducted to understand in situ stress state at 300 m depth.

Radiation processing using quantum beams

Tamada, Masao

Hoshasen Kagaku (Internet), (96), P. 1, 2013/09

Innovations in scientific technology are expected to revive the Japanese economy. Advantages of quantum beam technology are to be able to develop materials which have novel properties and superior functionality to those achieved by chemical methods. Such materials are favorable for technology transfer since they have higher potential than conventional products. This point is advantageous in quantum beam technology. Hence, it is extremely important that research and development of both new technology of quantum beams and new seeds aiming at industrial applications.

Spatial variations in He/He ratios along a high strain rate zone, central Japan

Umeda, Koji; Kusano, Tomohiro; Ninomiya, Atsushi*; Asamori, Koichi; Nakajima, Junichi*

Journal of Asian Earth Sciences, 73, p.95 - 102, 2013/09

https://doi.org/10.1016/j.jseaes.2013.04.016

A linear zone with high strain rates along the Japan Sea coast, the Niigata-Kobe Tectonic Zone (NKTZ), is considered to be associated with rheological heterogeneities in the lower crust and/or upper mantle. Helium isotope variations along the NKTZ reveal a close association with the geophysical evidence for rheological heterogeneities in the crust and mantle. In the northern NKTZ where two large inland earthquakes occurred recently, there appear to be many samples with He/He ratios significantly higher than those observed in the fore-arc side of northeast Japan. A plausible source of mantle helium could be attributed to upward mobilization of aqueous fluids generated by dehydration of the subducting Pacific Plate slab.

Change of Si(110) reconstructed structure by Ge nanocluster formation

Yokoyama, Yuta; Yamazaki, Tatsuya; Asaoka, Hidehito

Journal of Crystal Growth, 378, p.230 - 232, 2013/09

https://doi.org/10.1016/j.jcrysgro.2012.10.047

The initial processes of Ge nano cluster formation on Si(110)-162 reconstructed structure were investigated via scanning tunneling microscopy. For a small amount of Ge deposited on Si(110)-162 single-domain structure at room temperature, the surface structure did not change significantly. After direct current heating at 973 K for 20 min, the striped structure almost broken and disordered-like structure was formed on the terrace. With increasing the annealing time, the surface structure changed from disordered-like structure to the 162 double-domain structure and pyramidal nano clusters were formed at the domain boundary. These results suggest that the surface stress was induced by Ge nano cluster formation and the double-domain structure was formed in order to relax the stress.

Current-induced spin polarization on a Pt surface; A New approach using spin-polarized positron annihilation spectroscopy

Kawasuso, Atsuo; Fukaya, Yuki; Maekawa, Masaki; Zhang, H.; Seki, Takeshi*; Yoshino, Tatsuro*; Saito, Eiji*; Takanashi, Koki*

Journal of Magnetism and Magnetic Materials, 342, p.139 - 143, 2013/09

https://doi.org/10.1016/j.jmmm.2013.04.006

Transversely spin-polarized positrons were injected near Pt and Au surfaces under an applied electric current. The three-photon annihilation of spin-triplet positronium, which was emitted from the surfaces into vacuum, was observed. When the positron spin polarization was perpendicular to the current direction, the maximum asymmetry of the three-photon annihilation intensity was observed upon current reversal for the Pt surfaces, whereas it was significantly reduced for the Au surface. The experimental results suggest that electrons near the Pt surfaces were in-plane and transversely spin-polarized with respect to the direction of the electric current. The maximum electron spin polarization was estimated to be more than 0.01 (1%).

Mechanical properties of friction stir welded 11Cr-ferritic/martensitic steel

Yano, Yasuhide; Sato, Yutaka*; Sekio, Yoshihiro; Otsuka, Satoshi; Kaito, Takeji; Ogawa, Ryuichiro; Kokawa, Hiroyuki*

Journal of Nuclear Materials, 442(1-3), p.S524 - S528, 2013/09

https://doi.org/10.1016/j.jnucmat.2012.10.038

Friction stir welding was applied to the wrapper tube materials, 11Cr-ferritic/martensitic steel, intended for fast reactors and defect-free welds were successfully produced. Then, the mechanical and microstructural properties of the friction stir welded steel were investigated. The hardness values of the stir zone were about 550 Hv, and they had hardly any dependence on the rotational speed, although they were much higher than that of the base material. However, tensile strengths and elongations of the stir zones were better at 298 K, compared to those of the base material. These excellent tensile properties were attributable to the fine grain formation during friction stir welding. A part of this study is the result of "Friction stir welding of the wrapper tube materials for Na fast reactors" carried out under the Strategic Promotion Program for Basic Nuclear Research by the Ministry of Education, Culture, Sports, Science and Technology of Japan.

The Relationship between the amount of oxidation and activation energy on the steam oxidation reaction of Zircaloy-4 cladding

Amaya, Masaki; Nagase, Fumihisa

Journal of Nuclear Materials, 440(1-3), p.457 - 466, 2013/09

https://doi.org/10.1016/j.jnucmat.2013.01.292

The relationship between oxidation amount and the activation energy of cladding oxidation by steam was investigated by thermogravimetry. Ring-shaped specimen which was prepared from a Zircaloy-4 cladding tube was hanged in a themobalance, and specimen weight gain due to oxidation was continuously measured in the temperature range from room temperature to 1400C under argon-steam gas flow. The activation energy of steam oxidation reaction was evaluated based on measured weight gains by applying a non-isothermal kinetics theory. It was found that the activation energy of oxidation depends on the amount of specimen weight gain. The activation energies showed constant values of -300 and -180 kJ/mol in the range between 30 and 120 g/m and above 120 g/m, respectively. The activation energy in the weight gain above 120 g/m agreed well with literature values. The specimen weight gains were formulated using obtained activation energies.

Evaluation of mechanical properties and nano-meso structures of 9-11%Cr ODS steels

Tanno, Takashi; Otsuka, Satoshi; Yano, Yasuhide; Kaito, Takeji; Oba, Yojiro*; Onuma, Masato*; Koyama, Shinichi; Tanaka, Kenya

Journal of Nuclear Materials, 440(1-3), p.568 - 574, 2013/09

https://doi.org/10.1016/j.jnucmat.2013.04.006

This study carried out mechanical tests and microstructure characterizations of several 9Cr and 11Cr-ODS tempered martensitic steels, and discussed the appropriate chemical composition range of 11Cr-ODS tempered martensitic steel from the viewpoint of high-temperature strength improvement. It was shown that the residual -ferrite fraction in 11Cr-ODS steel was successfully controlled to the same level as the 9Cr-ODS steel by selecting the matrix chemical compositions on the basis of the multi-component phase diagram. The tensile strength decreased with decreasing W content from 2.0 to 1.4 wt%. On the other hand, creep strength at 973 K did not degrade by the decreasing W content. Both tensile strength and creep strength increased with increasing population of the nano-sized oxide particles. Small angle X-ray scattering analysis revealed that titanium and excess oxygen contents were key parameters in order to improve the dispersion condition of nano-sized oxide particles.

Thermal conductivity of (NpPuAmCm)O solid solutions

Nishi, Tsuyoshi; Takano, Masahide; Akabori, Mitsuo; Arai, Yasuo

Journal of Nuclear Materials, 440(1-3), p.534 - 538, 2013/09

https://doi.org/10.1016/j.jnucmat.2013.02.076

To clarify the dependence of thermal conductivity on storage time of curium containing oxide, the authors prepared the sintered sample of (NpPuAmCm)O (x = 0.02, 0.04) solid solutions and evaluated the thermal conductivity. The thermal conductivities of (NpPuAmCm)O exponentially decreased with increasing storage duration. This result suggested that the degradation of the thermal conductivities was attributed to the accumulation of lattice defects by self-irradiation.

High temperature reaction between sea salt deposit and (U,Zr)O simulated corium debris

Takano, Masahide; Nishi, Tsuyoshi

Journal of Nuclear Materials, 443(1-3), p.32 - 39, 2013/09

https://doi.org/10.1016/j.jnucmat.2013.06.039

In order to clarify the possible impacts of sea salt deposit on the chemical and physical state of the fuel debris formed in the severe accident at Fukushima Daiichi Nuclear Power Plant, the high temperature reaction between sea salt deposit and (U,Zr)O simulated fuel debris (sim-debris) was examined in the temperature range from 1088 to 1668 K. The dense layer of calcium and/or sodium uranate formed on the surface of sim-debris pellet at 1275 K under airflow, with the thickness of over 50 m. When the oxygen partial pressure is low, calcium likely dissolve into the sim-debris to form solid solution. The diffusion depth was 5-6 m from the surface at 1275 K for 12 h. The crystalline MgO remains as the main residue stuck on the surface. A part of it can dissolve into the sim-debris depending on the temperature.

Evaluation of neutron nuclear data of Praseodymium-141 and -143

Minato, Futoshi

Journal of Nuclear Science and Technology, 50(9), p.873 - 882, 2013/09

https://doi.org/10.1080/00223131.2013.810125

For the next version of JENDL general purpose file, neutron nuclear data on Pr are evaluated considering cross sections and spectra provided from experiments in the fast neutron energy region up to 20 MeV. Total cross section is derived from optical model. Pre-equilibrium and direct-reaction processes are taken into account in addition to the compound process. The statistical model is applied to calculate the cross sections above the resolved resonance region. For unstable Pr nuclide having less experimental data, we use the same optical potential as Pr. The resolved resonance parameter remains unchanged from JENDL-4.0. The present evaluations are consistent with experimental data, reflecting new measured one. The evaluated data are compiled into an ENDF-formatted data file for the next version of JENDL.

Algorithm-based modeling of fractional ion abundance and rates of ionization and recombination for tungsten plasmas

Sasaki, Akira; Murakami, Izumi*

Journal of Physics B; Atomic, Molecular and Optical Physics, 46(17), p.175701_1 - 175701_11, 2013/09

https://doi.org/10.1088/0953-4075/46/17/175701

The fractional ion abundance and rates of ionization and recombination of multiple charged tungsten ions in magnetic fusion plasmas are investigated using a collisional radiative model. Using a computer algorithm to generate a complete set of atomic states to be included into the collisional radiative model, the level population and ion abundance are calculated taking a sufficient number of dieletronic recombination and excitation autoionization channels into account. The atomic data, such as energy levels and rates of radiative decay as well as autoionization are provided from the ab-initio calculation using the HULLAC. The ion abundance is shown to converge with respect to the size of the model in the temperature range of 100 eV to 5 keV, and the ratio between the abundances of W and W ions agrees well with an experimental result obtained without any artificial adjustment of atomic rates.

Local lattice distortion caused by short range charge ordering in LiMnO

Kodama, Katsuaki; Igawa, Naoki; Shamoto, Shinichi; Ikeda, Kazutaka*; Oshita, Hidetoshi*; Kaneko, Naokatsu*; Otomo, Toshiya*; Suzuya, Kentaro

Journal of the Physical Society of Japan, 82(9), p.094601_1 - 094601_6, 2013/09

https://doi.org/10.7566/JPSJ.82.094601

Thermal stability of BNCT neutron production target synthesized by lithium deposition and ion implantation

Ishiyama, Shintaro; Baba, Yuji; Fujii, Ryo*; Nakamura, Masaru*; Imahori, Yoshio*

Materials Transactions, 54(9), p.1760 - 1764, 2013/09

https://doi.org/10.2320/matertrans.M2013062

LiN synthesis on Li deposition layer was conducted without HO and O by lithium deposition in high vacuum chamber of 10 Pa and ion implantation techniques and the thermo-chemical stability of the LiN/Li/Cu tri-layered target under laser heating and air exposure was characterized by X-ray photoelectron spectroscopy. Following conclusions were derived; (1) LiN/Li/Cu tri- layered target with very low oxide and carbon contamination was synthesized by lithium deposition and ion implantation techniques without HO and O additions and frequent synthesis of the target is possible. (2) The evaporating temperature of Li deposited layer increased by 120 K after forming the LiN layer on the surface of Li. (3) Remarkable oxidation and carbon contamination were observed on the surfaces of Li/Cu and LiN/Li/Cu after air exposure and these contaminated compositions formed on the surface of LiN/Li/Cu was not removed by Ar heavy sputtering.

Ge diffusion and bonding state change in metal/high-/Ge gate stacks and its impact on electrical properties

Hosoi, Takuji*; Hideshima, Iori*; Tanaka, Ryohei*; Minoura, Yuya*; Yoshigoe, Akitaka; Teraoka, Yuden; Shimura, Takayoshi*; Watanabe, Heiji*

Microelectronic Engineering, 109, p.137 - 141, 2013/09

https://doi.org/10.1016/j.mee.2013.03.115

Elasto-plastic and fracture modeling of concretes for determining the mechanical behaviour of the plug in the GAST project

Sanada, Hiroyuki; Teodori, S.*; Redi, J.*; Vomvoris, S.*

Nagra NAB 13-76, 43 Pages, 2013/09

GAST (Gas-Permeable Seal Test), an ongoing project in Phase VI at the Grimsel Test Site (GTS), is a large-scale demonstration test focusing on water movement during the early saturation phase and gas migration during the later gas invasion phase. In this report, the mechanical behaviour (e.g. stress, deformation, tension failure, elasto-plastic energy) of the massive concrete plug and surrounding rock mass of the GAST project are analyzed based on numerical modelling using the three-dimensional finite difference method.

Study on dismantling scenario for large equipment in decommissioning of nuclear facilities; Utilization of validation result of applicability of project management data evaluation code to decommissioning project of FUGEN

Shibahara, Yuji; Usui, Hideo; Izumo, Sari; Izumi, Masanori; Tezuka, Masashi; Morishita, Yoshitsugu; Kiyota, Shiko; Tachibana, Mitsuo

Nihon Genshiryoku Gakkai Wabun Rombunshi, 12(3), p.197 - 210, 2013/09

https://doi.org/10.3327/taesj.J12.031

As the first step of the applicability inspection of PRODIA Code for dismantling activities in the decommissioning of FUGEN, manpower needs for dismantling activities in FUGEN conducted in 2008 were calculated with conventional calculation formulas which were made by data obtained from JPDR decommissioning program. Since the conventional calculation formula for dismantling of feedwater heater has no applicability, the new calculation formula was constructed by reflecting the work description of dismantling of feedwater heater in FUGEN. It was found that the calculation results with this new formula showed the good agreement with the actual data both of 3rd feedwater heater and 4th one. Based on this discussion, some case studies for dismantling of feedwater heater were conducted.

Chemical interface controlled dispersion and high-speed shearing washing techniques for radioactive contaminated soil; 4th report of field test in Fukushima

Ishiyama, Shintaro; Mamitani, Masataka*; Kondo, Mitsunori*

Nihon Kikai Gakkai 2013-Nendo Nenji Taikai Koen Rombunshu (DVD-ROM), 5 Pages, 2013/09

Chemical interface controlled dispersion and high speed shearing (CDS) washing verification test of high level radioactive contaminated soil over 570,000 Bq/kg was conducted using three kinds of radioactive contaminated soils of school ground, moor and road in FUKUSHIMA and the following results was obtained. (1) Washing rate of three kinds of contaminated soils reached up to 6098% after 60minitues CDS water washing. (2) Recovered amounts of reclamation soils of three type of soils ( 8,000Bq/kg) were 6082wt.%. Especially, 506 Bq/kg 33wt.% was achieved in the case of contaminated soil of moor. (3) Volume reductions of 6085wt% were achieved in every case of contaminated soils. (4) Contain recoverable quantities of total radioactive sources contained in soils was over 90%. (5) Main FP trapping minerals contained in contaminated soil of school ground is lamellar silicate and that of moor and road is mordenite.

Numerical simulation of two-phase bubbly flow in an upward vertical pipe by use of interface tracking method

Jiao, L.; Yoshida, Hiroyuki; Takase, Kazuyuki

Nihon Kikai Gakkai Kanto Shibu Ibaraki Koenkai 2013 Koen Rombunshu, p.107 - 108, 2013/09

In Japan Atomic Energy Agency, the detailed two-phase flow analysis code TPFIT has been developed to simulate and evaluate two-phase flow characteristics in nuclear systems. In this study, a numerical simulation of bubbly flow in a vertical circular pipe was performed to validate the applicability of TPFIT code on bubbly flow simulation. By checking bubble distribution development in the flow direction, the calculation of the forces acting on bubbles was validated through comparing simulation results and experimental results from Lucas et al. (2005), who used wire-mesh sensor to obtain a high resolution of the gas fraction data in space as well as in time.

Establishment of CAE system for analyzing hydrogen diffusion, burning and explosion, and its impact development of

Terada, Atsuhiko; Kamiji, Yu; Takegami, Hiroaki; Hino, Ryutaro

Nihon Kikai Gakkai Kyushu Shibu Koenkai Koen Rombunshu, p.7 - 8, 2013/09

Aiming to enhancing basic technology for hydrogen safety evaluation and measures in decommissioning and waste management, Japan Atomic Energy Agency is conducting development of hydrogen mixture flow analysis system on the transition of hydrogen generation, diffusion, combustion and explosion. In this report, we provide outline of developed analysis system and results of hydrogen dispersion analysis and experiment.

Analysis of multi-fragmentation reactions induced by relativistic heavy ions using the statistical multi-fragmentation model

Ogawa, Tatsuhiko; Sato, Tatsuhiko; Hashimoto, Shintaro; Niita, Koji*

Nuclear Instruments and Methods in Physics Research A, 723, p.36 - 46, 2013/09

https://doi.org/10.1016/j.nima.2013.04.078

The fragmentation cross-sections of relativistic-energy nucleus-nucleus collisions were analyzed by SMM (Statistical Multi-fragmentation Model) incorporated with the Monte-Carlo radiation transport simulation code PHITS (Particle and Heavy Ion Transport code System). Comparison with literature data shows PHITS-SMM reproduces fragmentation cross-sections of heavy nuclei in relativistic-energies better than PHITS by up to two orders of magnitude. It is also found that SMM does not degrade neutron production cross-sections in heavy ion collisions or fragmentation cross-sections of light nuclei, for which SMM have not been benchmarked. Therefore, SMM is a robust model to supplement conventional nucleus-nucleus reaction models for more accurate prediction of fragmentation cross-sections.

Ground state phase diagram of an two-leg Heisenberg spin ladder system with negative four-spin interaction

Hijii, Keigo; Sakai, Toru

Physical Review B, 88(10), p.104403_1 - 104403_8, 2013/09

https://doi.org/10.1103/PhysRevB.88.104403

We investigate the ground-state phase diagram and critical properties of the two-leg Heisenberg spin ladder system with a negative four-spin interaction. We numerically determine a phase boundary between the rung singlet phase and the columnar dimer (CD) phase by the phenomenological renormalization group method, and one between the CD phase and the Haldane phase by the twisted boundary condition method. We confirm that the phase transition between the CD phase and the Haldane phase is of second order and this universality class is described by the = 2 (2) Wess-Zumino-Novikov-Witten nonlinear model, calculating the central charge and scaling dimensions.

Issues on the absolute neutron emission measurement at ITER

Sasao, Mamiko*; Ishikawa, Masao; Yuan, G.*; Patel, K.*; Jakhar, S.*; Kashchuk, Y.*; Bertalot, L.*

Plasma and Fusion Research (Internet), 8(Sp.1), p.2402127_1 - 2402127_3, 2013/09

https://doi.org/10.1585/pfr.8.2402127

Fusion power output of ITER is measured by a group of neutron flux monitors combined with a neutron activation system and neutron profile monitors. These systems should be absolutely calibrated by use of DD/DT generators moving inside the ITER vacuum vessel (in-situ calibration). Each neutron monitor has a limited measurement range of emission rate, but the ranges are connected by cross-calibration using the ITER plasma with at least one decade overlapping. The over all dynamic range covered by the group of neutron flux monitors is 10 n/sec to 10 n/sec. Effects of vertical/radial movement of plasma on the measurement accuracy were reviewed. It was found that cross-calibration using specially planned jog shots, and a vertical neutron camera is important to minimize the inaccuracy caused by the plasma movement.

Development of evaluation models of manpower needs for dismantling the dry conversion process-related equipment in Uranium Refining and Conversion Plant (URCP)

Izumo, Sari; Usui, Hideo; Tachibana, Mitsuo; Morimoto, Yasuyuki; Takahashi, Nobuo; Tokuyasu, Takashi; Tanaka, Yoshio; Sugitsue, Noritake

Proceedings of 15th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2013) (CD-ROM), 9 Pages, 2013/09

https://doi.org/10.1115/ICEM2013-96097

Distribution of radioactive cesium in trees and effect of decontamination of forest contaminated by the Fukushima nuclear accident

Iijima, Kazuki; Funaki, Hironori; Tokizawa, Takayuki; Nakayama, Shinichi

Proceedings of 15th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2013) (CD-ROM), 6 Pages, 2013/09

In decontamination pilot projects conducted by Japan Atomic Energy Agency (JAEA), many different techniques were tested to determine their applicability to remediate areas evacuated after the Fukushima Daiichi nuclear accident. The projects evaluated the radioactive contamination of trees and the effectiveness of decontaminating a highly contaminated evergreen forest. As the first step, three Japanese cedar trees and three fir trees were cut down and the distributions of radioactive cesium (Cs) were measured in each. The total concentrations of Cs and Cs in the leaves and branches were about 1 MBq/kg for both cedar and fir trees, and were appreciably higher than in the bark for cedar. The concentrations in the outer part of the trunks (under the bark) were lower, on the order of 10 kBq/kg, and those in the core of the trunks were lower than 1 kBq/kg for both kinds of trees. The observation that the Cs concentrations are higher in the outer part of trees, is compatible with the assumption that radio-Cs was mostly adsorbed on the surface of trees and partly penetrated into the trunks through the bark. Evolution of air dose rates in a 10060 m pasture adjacent to the forest was monitored during decontamination of the forest and of the pasture itself. The dose rates in the pasture decreased drastically after stripping contaminated topsoil from the pasture and decreased slightly more after stripping contaminated topsoil of the forest floor and pruning the trees. Cutting down and removing 84 trees in the outermost area (10-m width) of the forest also slightly decreased these dose rates. After decontamination, the residual dose rates around the highly contaminated forest were mostly attributed to radioactive Cs existing in or on trees and topsoil in the untouched forest beyond the decontaminated area.

Numerical analysis of heat transfer enhancement by spacers in subchannels at supercritical pressure condition

Takase, Kazuyuki; Misawa, Takeharu; Yoshida, Hiroyuki

Proceedings of 4th International Conference on Jets, Wakes and Separated Flows (ICJWSF 2013) (CD-ROM), 6 Pages, 2013/09

For the thermal design of supercritical water reactors, it is necessary to develop an analysis method to correctly predict turbulent heat transfer characteristics in subchannels of fuel bundles. Spacers are set into the subchannels to keep a distance between adjacent fuel rods. The turbulent heat transfer generally enhances by reduction of cross-sectional area in the subchannels due to the existence of the spacers. However, since thermo-physical properties of supercritical fluids drastically change at the vicinity of the pseudocritical point, the enhancement of the turbulent heat transfer depends on the thermal design. Then, the Japan Atomic Energy Agency is developing the analysis method to predict thermal-hydraulic characteristics of the supercritical fluids. The heat transfer calculations were performed using a newly developed code under the condition of a subchannel with a specer, and the enhancement of the turbulent heat transfer coefficient in subchannels with the spacer was analyzed numerically.

Plutonium partitioning in uranium and plutonium co-recovery system for fast reactor fuel recycling with enhanced nuclear proliferation resistance

Nakahara, Masaumi; Koma, Yoshikazu; Nakajima, Yasuo

Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.539 - 542, 2013/09

In order to develop a fast reactor fuel reprocessing, countercurrent extraction experiments for Pu reduction partitioning method with hydroxylamine nitrate and acid split method without Pu reductant were carried out. In the Pu reduction method, a part of U was co-recovered with Pu because the U scrubbing part can be deleted in the Pu partitioning section. On the other hand, acid split method experimental results indicate that almost all Pu was recovered with U by supplying diluted HNO solution in the Pu partitioning section. This study shows that not only Pu reduction partitioning but also acid split methods are effective for fast reactor fuel reprocessing.

Major safety and operational concerns for fuel debris criticality control

Tonoike, Kotaro; Sono, Hiroki; Umeda, Miki; Yamane, Yuichi; Kugo, Teruhiko; Suyama, Kenya

Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.729 - 735, 2013/09

JAEA is conducting studies on criticality control of the fuel debris formed in the accident of Fukushima-Daiichi site. A new control principle must be established, referring principles for existing facilities, and based on criticality characteristics of the debris. In accordance with the principle, safe and practical control has to be realized for the debris whose condition is uncertain at present. This report outlines the present condition of debris and Fukushima site, introduces examples of criticality analysis, and discusses control principles. Research subjects are also proposed to realize the control.

Study on release and transport of aerial radioactive materials in reprocessing plant

Amano, Yuki; Tashiro, Shinsuke; Uchiyama, Gunzo; Abe, Hitoshi; Yamane, Yuichi; Yoshida, Kazuo

Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.1411 - 1417, 2013/09

Recovery of minor actinides from spent fuel using TPEN-immobilized gels

Koyama, Shinichi; Suto, Mitsuo; Obayashi, Hiroshi; Oaki, Hiroshi*; Takeshita, Kenji*

Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.549 - 553, 2013/09

A series of separation experiments was performed in order to study the recovery process for minor actinides (MAs) from the actual spent fuel by using an extraction chromatographic technique. The 10 mol% TPPEN-gel was used to improve adsorption coefficient of Am and a condition of eluent temperature was changed in order to confirm the temperature swing effect on TPEN-gel for MA. More than 90% Eu was detected in the eluent after washing with 0.01M NaNO (pH 3.5) at 5C. Americium was backwardly detected and eluted continuously during in the same condition. After removal of Eu, the eluent temperature was changed to 32C, then Am was detected (pH 3.0). Finally remained Am could be stripped from TPPEN-gel by changing the pH of the eluent to 2.0.

Origin of the enhancement of electrocatalytic activity and durability of PtRu alloy prepared from a hetero binuclear Pt-Ru complex for methanol oxidation reactions

Okawa, Yukihisa*; Masuda, Takuya*; Uehara, Hiromitsu*; Matsumura, Daiju; Tamura, Kazuhisa; Nishihata, Yasuo; Uosaki, Kohei*

RSC Advances (Internet), 3(35), p.15094 - 15101, 2013/09

https://doi.org/10.1039/c3ra42816h

Optical designs of reflection and refraction collection optics for a JT-60SA core Thomson scattering system

Tojo, Hiroshi; Hatae, Takaki; Hamano, Takashi; Sakuma, Takeshi; Itami, Kiyoshi

Review of Scientific Instruments, 84(9), p.093506_1 - 093506_8, 2013/09

https://doi.org/10.1063/1.4821248

Influence of fracture orientation on excavatability of soft sedimentary rock using a hydraulic impact hammer; A Case study in the Horonobe Underground Research Laboratory

Tsusaka, Kimikazu; Tokiwa, Tetsuya

Tunnelling and Underground Space Technology, 38, p.542 - 549, 2013/09

https://doi.org/10.1016/j.tust.2013.08.007

In the Japanese deep geological disposal project for high-level radioactive waste, the ease of excavation of a potential host rock is a key issue for the economics of project implementation. This is because it is estimated that about 300-kilometers of disposal drifts will need to be excavated for the disposal of 40,000 waste packages deep underground. In this study, the influence not only of the mechanical properties of intact host rock, but also fracture characteristics and their effect on the practical excavation rate of drifts using a hydraulic impact hammer were analyzed. The drifts were excavated through soft sedimentary rock in the Horonobe Underground Research Laboratory. Fracture mapping was conducted at the excavation face before every excavation round for the evaluation of fracture characteristics. Equotip hardness testing was also conducted to estimate the strength of intact rock. The results indicate that the excavation rate of the drift excavated in the direction perpendicular to pre-existing fractures was faster than the excavation of the drift excavated in the direction parallel to pre-existing fractures. In addition, the drift excavated in the direction perpendicular to pre-existing fractures had a good correlation with fracture frequency. This result suggests that the preferred direction of disposal drifts should be perpendicular to the major pre-existing fractures in the host rock to optimize excavatability in any deep geological disposal project.

A New method to analyze Am in low-level radioactive waste based on extraction chromatography and -ray spectrometry

Shimada, Asako; Kameo, Yutaka; Takahashi, Kuniaki

Analytical Chemistry, 85(16), p.7726 - 7731, 2013/08

https://doi.org/10.1021/ac400918r

A new method for identifying Am in low-level radioactive waste (LLW) using -ray spectrometry is proposed. First, Eu, Am, and Cm in a digested solution of simulated LLW were separated from the major components of the digested solution and Pu using transuranium resin. Next, Am and Cm were separated from Eu using tetravalent actinide resin. A -ray spectrum of the fraction containing Am and Cm was recorded and the contribution of Np, which is a daughter nuclide of Am, was subtracted to determine the radioactivity of Am. The radioactivity of Am determined by -ray spectrometry agreed with that obtained by analyzing the increase in Cm in the Am fraction just after its separation from Cm with tertiary pyridine resin.

Neutron and X-ray crystallographic analysis of protease I at pD 8.0; Protonation states and hydration structure in the free-form

Onishi, Yuki*; Yamada, Taro*; Kurihara, Kazuo; Tanaka, Ichiro*; Sakiyama, Fumio*; Masaki, Takeharu*; Niimura, Nobuo*

Biochimica et Biophysica Acta; Proteins and Proteomics, 1834(8), p.1642 - 1647, 2013/08

https://doi.org/10.1016/j.bbapap.2013.05.012

The structure of the free-form of protease I (API) at pD 8.0 was refined by simultaneous use of single crystal X-ray and neutron diffraction data sets to investigate the protonation states of key catalytic residues of the serine protease. Occupancy refinement of the catalytic triad in the active site of API free-form showed that ca. 30% of the imidazole ring of H57 and ca. 70% of the hydroxyl group of S194 were deuterated. This observation indicates that a major fraction of S194 is protonated in the absence of a substrate. The protonation state of the catalytic triad in API was compared with the bovine -trypsin-BPTI complex. The comparison led to the hypothesis that close contact of a substrate with S194 could lower the acidity of its hydroxyl group, thereby allowing H57 to extract the hydrogen from the hydroxyl group of S194. H210, which is a residue specific to API, does not form a hydrogen bond with the catalytic triad residue D113. Instead, H210 forms a hydrogen bond network with S176, H177 and a water molecule. The close proximity of the bulky, hydrophobic residue W169 may protect this hydrogen bond network, and this protection may stabilize the function of API over a wide pH range.

Constraining the timing of brittle deformation and faulting in the Toki granite, central Japan

Yamasaki, Seiko*; Zwingmann, H.*; Yamada, Kunimi*; Tagami, Takahiro*; Umeda, Koji

Chemical Geology, 351, p.168 - 174, 2013/08

https://doi.org/10.1016/j.chemgeo.2013.05.005

Constraining of the timing of fault zone formation is of fundamental geotectonic importance to understand structural evolution and brittle fault processes. Here, we present authigenic illite K-Ar age data from brittle fault zones comprising two gouges within the Toki granite, central Japan. The gouge samples were collected from a shaft at the Mizunami Underground Research Laboratory, and were separated into five grain-size fractions. K-Ar ages of clay fractions decrease with grain size, suggesting enrichment in finer fraction of more-recently grown authigenic illites. The K-Ar ages of the fractions range from 53.6 to 42.7 Ma (Paleogene-Early to Middle Eocene). The 0.1 m fractions yield ages of 42.7 and 46.5 Ma. This age range is consistent with the stability field of illite and the main temperature field of brittle deformation within the cooling history of the Toki granite, supported by extensive thermochronological data of the host rock.

Study on piping response under multiple excitations; Triple shaking table test of piping having three-supporting anchors

Watakabe, Tomoyoshi; Kaneko, Naoaki*; Aida, Shigekazu*; Otani, Akihito*; Tsukimori, Kazuyuki; Moriizumi, Makoto; Kitamura, Seiji

Dynamics and Design Conference 2013 (D&D 2013) Koen Rombunshu (USB Flash Drive), 8 Pages, 2013/08

The piping in a nuclear power plant is laid across multiple floors of a single building or two buildings, which are supported at many anchors. As the piping is excited by multiple inputs from the supporting anchors during an earthquake, seismic response analysis by multiple excitations is needed to obtain the exact seismic response of the piping. However, few tests involving such multiple excitations have been performed to verify the validity of multiple excitation analysis. To perform rational seismic design and evaluation, it is important to investigate the seismic response by multiple excitations and verify the validity of the analysis method by multiple excitation test. This paper reports on the result of the shaking test using triple uni-axial shaking tables and a 3-dimensional piping model.

Behavior of the energy of vibration failure experiment by using a 2-mass system model

Seki, Hajime*; Fujita, Satoshi*; Minagawa, Keisuke*; Kitamura, Seiji; Watakabe, Tomoyoshi

Dynamics and Design Conference 2013 (D&D 2013) Koen Rombunshu (USB Flash Drive), 8 Pages, 2013/08

When we study the behavior of the pipes during an earthquake, the most important damage doesn't come from the maximal load by itself, but from the accumulation of the fatigue damage caused by the repetition of the cyclic load. Therefore, from the point of view of seismic design evaluation methods, techniques that can quantitatively assess the probability of fatigue failure of mechanical structures are needed. The relationship between failure and energy is evaluated, and examined by focusing on the Energy Balance Method said to be effective as an earthquake response analysis technique in the present. This study carries out failure experiments using 2-mass system model based on Energy Balance Method. Furthermore, we focus on the strain from the vicinity of broken point as local response.

Relativistic effects in scattering of polarized electrons

Sushkov, O. P.*; Milstein, A. I.*; Mori, Michiyasu; Maekawa, Sadamichi

EPL; A Letters Journal Exploring the Frontiers of Physics, 103(4), p.47003_1 - 47003_6, 2013/08

https://doi.org/10.1209/0295-5075/103/47003

photoproduction with evidence for the Kappa Meson Exchange at SPring-8/LEPS

Hwang, S. H.*; Hicks, K.*; Ahn, J. K.*; Nakano, Takashi*

Few-Body Systems, 54(7-10), p.1037 - 1041, 2013/08

https://doi.org/10.1007/s00601-013-0650-0

Evaluation of rock properties using a hydraulic rock drill at Mizunami Underground Research Laboratory

Hikima, Ryoichi*; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*; Sato, Toshinori; Sanada, Hiroyuki; Tanno, Takeo

Heisei-25 Nendo (2013 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.247 - 248, 2013/08

no abstracts in English

Magnetocaloric effect of field-induced ferromagnet BaFeO

Mizumaki, Masaichiro*; Yoshii, Kenji; Hayashi, Naoaki*; Saito, Takashi*; Shimakawa, Yuichi*; Takano, Mikio*

Journal of Applied Physics, 114(7), p.073901_1 - 073901_6, 2013/08

https://doi.org/10.1063/1.4818316

We have investigated the magnetocaloric effect (MCE) of a perovskite oxide, BaFeO, that shows ferromagnetism by the aid of a small external field of about 0.3 T below the Curie temperature T = 111 K. The magnetization is found to change almost reversibly in both field and temperature cycles. Hence, magnetic and thermal hysteretic losses are negligibly low during refrigeration, a property that is suitable for application. The reversible MCE is likely to arise from the absence of an orbital magnetic moment of Fe ions which are essentially in the FeL state (L: ligand hole). The magnetic entropy change and refrigerant capacity near the T are about 5.8 J kg K and about 172 J kg, respectively, both of which are comparable to those of ferromagnetic perovskite manganites. As BaFeO contains no rare metals and is stable against corrosion, the material can be regarded as a candidate refrigerant material.